In view of the Communications Assistance for Law Enforcement Act (CALEA), communications network operators need to provide for intercepting communications from an individual identified by a law enforcement agency and for providing the intercepted communications to the law enforcement agency. The law defines the existing statutory obligation of telecommunications carriers to assist law enforcement in executing electronic surveillance pursuant to court order or other lawful authorization and requires carriers to design or modify their systems to ensure that lawfully-authorized electronic surveillance can be performed.
FIG. 1 illustrates representative functions performed by a CALEA compliant communications network. As illustrated in FIG. 1, the functions generally include administration, access, and delivery.
The administration function 100 may be performed by an administrative data center and may include information related to a court's order for intercepting communications from a particular network user and the identity of the network user. The administrative data center sends commands to the access function 110 and delivery function 120 to manage all intercept sessions.
The access function 110 intercepts the subject network user's communication. The access function intercepts both call identifying information and call content information from the intercepted communication. Call identifying information is defined by CALEA as dialing or signaling information that identifies the origin, direction, destination, or termination of each communication generated or received by a subscriber by means of any equipment, facility, or service of a telecommunications carrier. Call content information includes any information concerning the substance, purport, or meaning of the communication. The access function provides the intercepted call identifying information and call content information to the delivery function.
The delivery function 120 delivers the intercepted information received from the access function 110 to the law enforcement agency.
One proposed architecture for complying with CALEA requirements is illustrated in FIG. 2. However, there are drawbacks with the proposed architecture. As can be seen in FIG. 2, a user communicates with communications network 200 through a communications device 210. More specifically, the communications device 210 communicates with network infrastructure 220 through base station 230. The base station 230 receives a communication from device 210 and sends the communication to network infrastructure 220 through a communications link, which is typically a T1 line 231.
In the proposed architecture, the base station 230 serves as the access function for CALEA compliancy. In performing this functionality, the base station captures both the call identifying information and the call content information of the call and provides the captured call identifying information 232 and call content information 233 to the network infrastructure over the T1 link 231. This proposed architecture has drawbacks.
When capturing the call identifying information and the call content information for CALEA purposes, the base station records this information and transports it over the T1 link to the network infrastructure. However, in addition to transporting the recorded CALEA information over the T1 link, the original information of the communication, i.e., the call identifying information 234 and call content information 235, is also transported over the same T1 link 231. Since the call content information can require significant bandwidth, particularly in broadband wireless data networks, transportation of both the original call content information 235 and the captured call content information 233 over the T1 link 231 can very quickly exhaust the bandwidth capacity of the T1 link.
Therefore, because the T1 link has limited capacity and is relatively expensive, it is not desirable for a telecommunications network to transport the captured call content information from an access function to a network infrastructure over a T1 link. Therefore, it is desirable to provide an improved architecture and method for intercepting communications in a communications network.